What size and type of appliance is best?

Pellet stoves come in a wide range of style, size, and finish. Freestanding pellet stoves offer great flexibility in installation choices. Supported by a pedestal or legs, they are designed to be installed in almost any living area of the home with some restrictions applying to sleeping areas. Freestanding stoves are placed on a non-combustible floor protector and are installed a specified distance from combustible surfaces.

Fireplace inserts are installed in existing, working fireplaces. A decorative panel covers the space between the insert and the fireplace opening. Some pellet inserts are approved only for use in masonry fireplaces, while others can also be installed in approved factory-built metal fireplaces.

Built-in appliances are an economical choice that offers homes without an existing fireplace the look of an insert in a fireplace setting. A unit tested and listed as a built-in can be boxed in with close clearances to combustible framing. Noncombustible materials like brick can be applied to the area around the front of the unit to give the appearance of a fireplace. A noncombustible floor protector is required, sometimes with spacers to provide an air space under the unit.

Pellet furnaces are large units designed to heat an entire house through ductwork. They are usually installed in a basement or other non-living area of the house. Like pellet stoves, furnaces require venting to the outside.

Pellet stoves are also categorized according to their method of delivering fuel.

Top feed stoves deliver pellets from a tube or chute above the fire, and bottom feed stoves deliver pellets from behind or beside the burn pot directly to the fire. There are many variations within these categories, but in general, bottom feed stoves tend to perform better with the wider range of ash content in standard grade fuel because the feeding action moves ash and clinkers away from the burn area. This action helps keep air inlets open and thereby reduces the frequency of cleaning the burn pot. Top feed stoves may have some advantage in overall heating efficiency since pellets remain in the burn pot until they are completely burned, and exhaust gases tend to move slower, allowing improved heat transfer. Special grates or rotating burn pots in some top feed designs can also move ash and clinkers from the air inlets to reduce maintenance frequency. If only standard grade pellets are available, or if there is a desire to burn a higher ash or special fuel like corn or nut hulls, special attention must be paid to the issue of fuel delivery, ash content, and stove compatibility. Otherwise, design differences are less significant considerations of relative degrees of efficiency and maintenance frequency.

The wide range of heat output possible with pellet stoves reduces the number of different stove sizes needed for most heating situations. Within the range of pellet stove sizes, choices involve input from different sources. Information from manufacturers is of necessity general in nature given the many variables in climate, home construction, and personal comfort. Btu output and efficiency ratings must be qualified to be useful. Overall efficiency, a measurement of the percentage of the energy available in a fuel that is actually delivered as heat in the home, is more important than combustion efficiency, a measurement of the percentage of available energy that is converted to heat (some of which escapes through the vent).

What are the key features?

Stove size, type, and appearance generally begin the process of appliance selection. The choice may then include considerations of performance, convenience, and cost. A number of design features affect operational convenience.

Hopper capacity, which ranges from under 40 to over 100 pounds, plays a role in loading frequency. Hopper size should match heating needs on a reasonable loading cycle, typically once daily. The means of adjusting controls affect convenience also. Manually controlled stoves require occasional adjustment of air inlet dampers as the fuel feed rate is changed. Stoves with more sophisticated controls are able to monitor burn conditions and make these adjustments automatically. The choice may focus on the lower cost of manual stoves versus the value of minimal interaction with stove operation. Features that affect ash tolerance and fuel compatibility may influence both performance and convenience, particularly in regions where fuel grade choice is limited. While many newer stoves perform well with increasingly wider ranges of fuel, some designs are better at extending good performance with longer intervals between routine maintenance. Bottom fuel feeding moves ash and clinkers away from air inlets. Specially designed grates in top feed designs either allow heavier ash and clinkers to fall through to the ash drawer, or they rotate themselves to move ashes and keep air inlets open. In both stove designs, a larger ash drawer reduces ash removal frequency, and grates that can be dumped without stopping operation add convenience. As long as a compatible pellet fuel is available, the issue of ash tolerance is one of convenience, not the acceptability of stove design. Features that make routine cleaning tasks easier enhance ease of maintenance. The heat exchanger can be cleaned by simply moving an external rod handle back and forth on some stoves. Other designs demand a more involved cleaning procedure.

Although pellet stoves are safety tested as a solid fuel heater by an accredited laboratory, stoves safety tested to ASTM Standard E 1509 undergo stringent testing specifically designed for pellet appliances to assure their safety and performance reliability.

Other features bring added convenience and enjoyment:

1. Automatic ignition offers simple, reliable startup. Typically more desirous on stove used intermittently than on one used continuously.
2. Remote thermostatic control regulates heat output based on room temperature. Ensures even temperature from unattended stove regardless of changes in the weather. Discuss with the dealer the merits of thermostats and stove startup design: automatic ignition stoves cycle on and off according to heat demand; manual start stoves keep fire at low setting and return to high.
3. Large glass view and air wash system offers fire viewing, particularly enjoyable in living area installations. Air wash keeps glass clean by directing warm air over the glass during combustion.
4. Imitation log sets (stove manufacturer approved only) improves aesthetics of the fire. May increase frequency and difficulty of maintenance; ask if removable.
5. Blower quietness, which could be a concern in some areas of the house, depending on room use and personal preference.
6. Backup power source, which is a consideration for primary heat stoves in areas subject to frequent power outages. Should automatically switch from utility power to battery and back again.
7. Extended warranty for components. Low cost, high value extension of warranty on components (from one or two years to as many as five).

What about pellet appliance dealers?

Pellet stoves are not difficult to operate or maintain with some initial instruction. Inquiries should be made into what owner training materials and services are available before purchasing. Support after the sale adds value to the purchase price. Many dealers offer training through stove operation demonstration and newsletters, in addition to the instructional manuals and videos provided by manufacturers. Dealers can provide details of warranty service, including extended warranty plans, as well as regular (usually annual) service. Dealers may discuss a fuel plan detailing what locally available fuels are compatible with the purchased appliance and what sources supply them.